We investigated how cells in the visual pathways of the primate respond to stimuli during rapid or saccadic eye movements. In the striate cortex only about half of the supragranular cells responded to stimuli as the eye swept the receptive field of a cell across the stimulus while nearly all infragranular cells responded. Visual masking by stimuli falling on the receptive field of a cell before and after a saccade was effective in reducing the response of the cell to the stimulus during the saccade. Forward masking was more prolonged than backward masking. A similar masking effect was found in the monkey superior colliculus. In addition a corollary discharge was found in the superior colliculus. The visual masking effect in striate cortex appears to be cosely related to lack of perception during saccadic eye movements while the corollary discharge to the superior colliculus is probably most closely related to the initiation of saccades.